1. Field of the Invention
The present invention relates to a display apparatus and a light source device used in the display apparatus. More particularly, the present invention relates to a display apparatus having a high cost-effectiveness and a light source device used in the display apparatus.
2. Description of Related Art
Since a light-emitting diode (LED) has advantages of long lifespan, small-size, high shock-resisting capability, low heat-irradiation and low power consumption, etc., it has been widely applied to backlight modules of flat panel displays and a general illumination domain. During a fabrication process of the LED, due to differences of time, temperature, machine and material or other variation factors in the fabrication process, quality of each completed LED is slightly different. Therefore, after the fabrication, the LEDs are further tested and classified, so as to classify the LEDs into different bins. Generally, a classification standard of the LEDs includes a wavelength, a light-emitting intensity, a light-emitting angle, a chromaticity or a working voltage, etc.
The chromaticity is generally used as the classification standard for classifying white LEDs used in a display apparatus. Since human eyes are sensitive to colors, if unclassified white LEDs are used as a light source of the display apparatus, a user may easily feel an uneven brightness or a color shift phenomenon of a screen. In other words, an overall visual effect represented by the display apparatus is influenced. Therefore, a requirement for the chromaticities of the white LEDs used in the display apparatus is rather high. Generally, only a few white LEDs of which bins being around a white center of a chromaticity coordinate diagram are used.
However, in the white LEDs of a same production lot, there are only a small number of the white LEDs with the chromaticities thereof falling around the white center of the chromaticity coordinate diagram, so that cost of the white LEDs is relatively high. Therefore, to maintain the display quality of the display apparatus, the cost of the white LEDs cannot be reduced.